Three phase semi converter drive

• The circuit diagram of 3 phase semi-converter feeding a separately excited dc motor is shown in the figure.
• Shown in the figure, the field winding of the motor is also connected to the three-phase semi-converter. 
• This drive offers one quadrant operation and is used up to about 115 kW ratings.

Figure - 3-phase semi converter feeding a separately excited dc motor

For converter 1,     V₀  = V _t  = 3V_ml/2∏ * (1 + Cos  ɖ  )  for 0 <  ɖ  <  ∏

For converter 2,    V_f   = 3V_ml/2∏ * (1 + Cos  ɖ₁  )    for 0 <  ɖ₁ <  ∏